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win32: MD5sums

MD5sums 1.2 - Generate MD5 hashes of files (with progress indicator)

Download: md5sums-1.2.zip [28 K]
This is a win32 console application. There is no GUI, but you can use Explorer to drag files over md5sums.exe to obtain their md5 hashes.
PGP/GPG signature: md5sums-1.2.zip.asc [use author's key, above]

MD5sums calculates the MD5 message digest for one or more files (includes a percent done display for large files). By comparing the MD5 digest of a file to a value supplied by the original sender, you can make sure that files you download are free from damage and tampering. MD5 values are frequently supplied along with downloadable files.
(Optimized implementation).

Changes in version 1.2

Features

MD5sums has user-friendly output, including a percent done indicator
when processing large files. With its various command line switches
you can customize MD5sums for use in scripts.

The UNIX compatibility switch (-u) makes the output look like that
from the Linux/BSD/UNIX md5 or md5sum commands.

Besides the normal command line usage (see md5sums.txt), MD5sums
can also be easily added to the windows shell. Use Windows Explorer
to access your user profile directory (one level up from the "Start
Menu" directory). Locate the "SendTo" folder and create a shortcut
inside it to "md5sums -p" (pause before returning).

If you have trouble locating your user profile directory, try this
at the command prompt: echo %userprofile%

After adding MD5sums to the SendTo folder, you can select one or
more files on the desktop (or in any other folder), and right-click
to "Send To" md5sums. Each selected file will be processed.

ABOUT THE MD5 PROCESS

[Paraphrased and, in parts, quoted from RFC 1321]

The MD5 Message Digest Algorithm takes an input (in this case, a
file) and produces a 128-bit (or 16 byte) output, which can be
represented as a string of 32 hexadecimal values. This output is
a 'fingerprint' or 'message digest' for the file.

You will often find an MD5 value supplied along with files you
download off of the internet. By comparing the supplied MD5 value
to the actual value computed by the MD5sums utility, you can make
sure that the file has not been tampered with or modified.

"It is conjectured that it is computationally infeasible to
produce two messages having the same message digest, or to
produce any message having a given prespecified target message
digest."

In the context of this MD5sums utility, what this means is: if
you have a file and know what the MD5 value should be, and this
value matches the actual MD5 value obtained by using the MD5sums
utility, then the file is very likely the original file.

This is a good way to both verify that the file has not been
damaged during electronic transfers, and also to verify that the
file you are getting has not been tampered with.

For example, the MD5 value of md5sums.exe is:
da1e100dc9e7bebb810985e37875de38

Note that recent research has shown that MD5 computations are not
as immune to collisions as thought earlier. While MD5 hashes are
still excellent for file comparisons, for cryptographic strength
it is recommended that one uses a stronger hash such as SHA-2.